(1) Field of the Invention
The present invention relates to a rubbery polymer composition. More specifically, the present invention relates to a rubbery polymer composition, which is superior in scratch resistance, oil resistance and mechanical strength.
(2) Description of the Related Art
A thermoplastic elastomer composition obtained by so-called dynamic vulcanization is already known in the art and extensively applied for various uses such as car parts. According to the dynamic vulcanization, a radically vulcanizable elastomer and a resin having no radically vulcanizing property such as polypropylene (PP) are subjected to vulcanization, while melt-kneading in the presence of a radical initiator in an extruder.
As such a rubber composition, an olefinic elastomer obtained using ethylene-propylene-diene rubber (EPDM) is known (JP-A-8-120127 and JP-A-9-137001), and a dynamic vulcanization technology using the same is also known. However, such a rubber composition is inferior in its scratch resistance, and therefore it is not always satisfied in the market.
On the other hand, as a dynamic vulcanization technology using a saturated rubber, for example, there is known a dynamic vulcanization elastomer composition (JP-A-9-302156), which is obtained by using an olefinic copolymer rubber as the main constituent and a hydrogenated diene rubber as an auxiliary constituent and further blending a crystalline α-olefinic polymer, an ethylene polymer and a softening agent. Further, there is known a thermoplastic elastomer composition (JP-A-3-2240), which is obtained by melt-mixing a polyolefinic resin and a random or block copolymer of conjugated diene-aromatic vinyl monomer in the presence of a vulcanizing agent. The above-mentioned compositions are not always sufficient in their mechanical strength, scratch resistance, appearance and heat and light stability, and therefore a rubber composition sufficient to practical applications has been desired.